TECHNICAL FIELD
[0001] The present disclosure relates to an optical amplification method and an amplifier
in a technical field of optical communication, and in particular to a self-adaptive
wave band amplification method and an amplifier.
BACKGROUND
[0002] With higher and higher requirements in optical communication industry in aspects
of transmission bandwidth and optical signal-to-noise ratio, a traditional C band
erbium-doped fiber amplifier gradually appears to be more and more limited in regard
to a noise figure and amplifying bandwidth.
[0003] A C+L band Raman or Hybrid amplifier is widely sought after for combining two excellent
characteristics of low noise figure and wide band amplification into a whole. However,
what is currently used is basically a traditional C band Raman/Hybrid optical amplifier,
which cannot be smoothly replaced and upgraded to the C+L band Raman optical amplifier,
the cost of replacement and upgrade being high. Although a few of C+L band Raman/Hybrid
optical amplifiers have been configured, they are not self-adaptive or extensible,
and therefore a manual judgment at a level of network management is required on whether
a signal band is C/L/C+L, and ON/OFF of each Raman pump unit is configured manually.
Such control manner is primitive and extensive, and configuration efficiency is too
low.
SUMMARY
[0004] The present disclosure aims at the above existing technical problems, and provides
a self-adaptive wave band amplification method and an amplifier. Through the amplification
method and amplifier, the traditional C band Raman/Hybrid is modified, extended and
upgraded to the C/C+L band Raman/Hybrid, and Raman/Hybrid amplification wave band
may be intelligently and adaptively turned on, turned off and adjusted. In addition,
the self-adaptation and extensibility provided in the present disclosure is to perform
direct detections, interactions and actions from bottom layers of function units,
and therefore, the response speed is high and the resource cost is low.
[0005] The above-mentioned technical problems presented in the present disclosure are primarily
solved by the following technical solutions.
[0006] A self-adaptive wave band amplification method comprises:
a light splitting step for detecting C band detection light and L band detection light
in an in-band signal; and
a scheduling module for enabling a slave Raman amplifying unit to participate in amplification
after the L band detection light is detected.
[0007] For example, in the above self-adaptive wave band amplification method, the scheduling
module enables a master Raman amplifying unit after the C band detection light and/or
the L band detection light is detected.
[0008] For example, the above self-adaptive wave band amplification method further comprises
a wave combining step for performing wave combination/splitting by using two optical
wavelength division multiplexers (OWDMs) after the slave Raman unit injects its pumping
light into the master Raman unit, the wave combination comprising:
injecting pump light from the master Raman amplifying unit into a transmission fiber
after wave combining/splitting once, and injecting pump light from the slave Raman
unit into the transmission fiber after wave combining/splitting twice; or
injecting the pump light from the slave Raman unit into the transmission fiber after
wave combining/splitting once, and injecting the pump light from the master Raman
unit into the transmission fiber after wave combining/splitting twice; or
performing a first wave combination for the pump light from the master and slave Raman
units and then a second wave combination with signal light.
[0009] For example, in the above self-adaptive wave band amplification method, a work flow
of a Raman amplifying unit includes following steps:
step 4.1, determining whether a pump-starting condition is met, and executing step
4.2 if yes;
step 4.2, turning on a Raman unit pump with a preset small optical power value; returning
to step 4.1 when it is determined that the pump-starting condition is not met, or
executing step 4.3 when it is determined that a reflection coefficient does not exceed
a threshold;
step 4.3, configuring pump power according to a comparison between light power of
each band in signal light and a corresponding threshold, and returning to step 4.1
when it is determined that the pump-starting condition is not met, and executing step
4.2 when it is determined that the reflection coefficient exceeds the threshold.
[0010] For example, in the above adaptive wave band amplification method, in the step 4.3,
selecting different working modes for the master Raman unit pump according to the
comparison; and
increasing pump optical power of the slave Raman unit to a target value according
to the comparison.
[0011] A self-adaptive band amplifier, comprises:
a light splitting module for detecting C band detection light and L band detection
light in an in-band signal;
a scheduling module for enabling a slave Raman amplifying unit to participate in amplification
after the L band detection light is detected.
[0012] For example, in the above self-adaptive band amplifier, the light splitting module
comprises: a first signal light splitter for splitting the in-band signal, and a first
optical wavelength division multiplexer connected with the first signal light splitter,
output ends of the first signal light splitter being respectively connected with a
first photodetector and a second signal light splitter for a master Raman amplifying
unit, and the second signal light splitter being connected with a first photodetector
for the slave Raman amplifying unit.
[0013] For example, in the above self-adaptive band amplifier, pump light emitted from a
slave Raman amplifying unit pump is injected into the master Raman amplifying unit,
passes through a first pump light splitter and is combined with the in-band signal
light at a second optical wavelength division multiplexer, and then is combined at
the first optical wavelength division multiplexer with pump light emitted from a master
Raman amplifying unit pump split by a second pump light splitter.
[0014] For example, in the above self-adaptive band amplifier, pump light emitted from the
master Raman amplifying unit pump passes through a second pump light splitter and
is combined with the in-band signal light at the first optical wavelength division
multiplexer, and then is combined at a second optical wavelength division multiplexer
with pump light from the slave Raman amplifying unit processed by the first pump light
splitter.
[0015] For example, in the above self-adaptive band amplifier, pump light emitted from the
master Raman amplifying unit pump and pump light emitted from the slave Raman amplifying
unit pump are split respectively by the first pump light splitter and the second pump
light splitter and combined at the optical wavelength division multiplexer, and then
combined with the in-band signal light by another optical wavelength division multiplexer.
[0016] Therefore, the present disclosure has the following advantages: (1) the present self-adaptive
wave band amplifier is composed of two portions of the master amplifying unit and
the slave amplifying unit, and may independently detect the service signal band range
of an optical transmission line; (2) the two amplifying units need not be scheduled
and configured from the level of network management, but directly interact and act
from the bottom layers to be turned on, turned off and adjusted self-adaptively in
real time; (3) it not only may reduce power consumption and save energy, but also
may optimize the performance and obtain an optimal optical amplification index.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017]
- FIG. 1
- shows an architectural form 1 of a C+L Raman optical amplifier.
- FIG. 2
- shows an architectural form 2 of a C+L Raman optical amplifier.
- FIG. 3
- shows an architectural form 3 of a C+L Raman optical amplifier.
- FIG. 4
- is a working flowchart of a master Raman unit.
- FIG. 5
- is a working flowchart of a slave Raman unit.
[0018] In FIGs. 1, 2, and 3, thick arrows indicate a propagation direction of a Raman pump
light, and thin arrows indicate a propagation direction of signal light as signal
detection light.
DETAILED DESCRIPTION OF EMBODIMENTS
[0019] The technical solutions of the present disclosure are further described below with
reference to the embodiments and the drawings.
Embodiments:
[0020] Through C/L WDM, a master Raman amplifying unit separates signal light into C band
signal light and L band signal light. The two bands of signal light are respectively
detected, and the L band signal light is introduced to a slave Raman amplifying unit.
When only the C band signal light exists, only the master Raman amplifying unit actively
participates in amplification. And once the L band signal light is added, it will
surely be captured by the master Raman amplifying unit and the slave Raman amplifying
unit, and triggers the two Raman amplifying units to act correspondingly. The master
Raman amplifying unit will adjust its own working states, meanwhile, the slave Raman
amplifying unit will turn on and participate in amplification. Once the L band signal
is lost, the slave Raman amplifying unit will automatically turn off. On the other
hand, when a C band service signal and a L band service signal both are lost, the
master Raman unit will automatically turn off, and the master Raman unit is automatically
turned on and enabled as long as the service signal is recovered. For the master Raman
unit, when the C band signal and the L band signal both exist, only the C band signal
exists or only the L band signal exists, the master Raman unit is turned on, and respectively
works in three configuration manners. When only the L band signal exists and the C
band signal and L band signal both exist, the slave Raman unit is enabled.
[0021] After the slave Raman unit injects its pump light into the master Raman unit, a wave
combination/splitting will be performed by using two optical wavelength division multiplexers
in three manners.
[0022] The first manner is that pump light from the master Raman unit is combined/split
once and then injected into a transmission fiber, while pump light from the slave
Raman unit needs to be combined/split twice and then injected into the transmission
fiber, as shown in FIG. 1. In FIG. 1, the pump light emitted from a Raman amplifying
unit pump 3-2 is injected into the master Raman amplifying unit, passes through a
first pump light splitter 4-1 and is split a small amount into a first photodetector
5-1, while the light on the main path passes through a second optical wavelength division
multiplexer 2-2 and is combined with in-band signal light. Then, the pump light from
the slave Raman amplifying unit pump 3-2 and the pump light from the master Raman
amplifying unit pump 3-1 is combined by the first wavelength division multiplexer
2-1 and then is injected into a transmission fiber 1 together. The master Raman amplifying
unit pump 3-1 is split via the first pump light splitter 4-1, and a small amount of
the pump light enters a fifth photodetector 5-5 for the slave Raman amplifying unit,
while most amount of the pump light enters a first optical wavelength division multiplexer
2-1.
[0023] The in-band signal light is split via a second signal light splitter 4-2, and a small
amount of the in-band signal light enters a third optical wavelength division multiplexer
2-3 and then is divided into C band and L band for detection respectively. The C band
monitoring light enters a second photodetector 5-2, and the L band monitoring light
then enters a third signal light splitter 4-3 and is split into two beams of light,
one of which enters a third photodetector 5-3, and the other of which enters a fourth
photodetector 5-4 for the slave Raman amplifying unit.
[0024] The second manner is that the pump light from the slave Raman unit is combined/split
once and then injected into the transmission fiber, while the pump light from the
master Raman unit needs to be combined/split twice and then injected into the transmission
fiber, as shown in FIG. 2. The difference between FIG. 2 and FIG. 1 is that in FIG.
2 the pump light from the master Raman amplifying unit pump 3-1 is combined twice
by the first wavelength division multiplexer 2-1 and the second wavelength division
multiplexer 2-2, while the pump light from the slave Raman amplifying unit pump 3-2
is combined by the second wavelength division multiplexer 2-2 only once and then reaches
the transmission fiber 1.
[0025] The third manner is that the pump light from the master Raman unit and the pump light
from the slave Raman unit is performed a first combination, and then a second combination
with the signal light, as shown in FIG. 3. The difference between FIG. 3 and FIG.
1 is that in FIG. 3 the pump light from the master Raman unit pump 3-1 and the pump
light from the slave Raman unit pump 3-2 is combined by the second wavelength division
multiplexer 2-2, and then is combined with the signal light by the first wavelength
division multiplexer 2-1, finally reaches the transmission fiber 1.
[0026] In the above first manner, i.e. in FIG. 1, the master Raman pump that amplifies the
C band signal is combined/split only once and then enters the transmission fiber,
while the slave Raman pump that amplifies the L band signal is combined/split twice
and then enters the transmission fiber. In other words, in the first manner, the attenuation
experienced by the master Raman pump is relatively low, while the attenuation experienced
by the slave Raman pump is relatively large, that is to say, the first manner is more
beneficial to the C band signal amplification. In the second manner, i.e. in the FIG.
2, the master Raman pump that amplifies the C band signal is performed wave combination
and wave split twice and then enters the transmission fiber, while the slave Raman
pump that amplifies the L band signal is performed the wave combination and wave split
only once and then enters the transmission fiber. In other words, in the second manner,
the attenuation experienced by the master Raman pump is relatively large, while the
attenuation experienced by the slave Raman pump is relatively small, that is to say,
the second manner is more beneficial to the L band signal amplification. In the third
manner, both the master Raman pump and the slave Raman pump are performed the wave
combination and wave split twice before entering the transmission fiber, and the attenuation
experienced by both are relatively large, however, the signal light from the transmission
fiber to output from the Raman optical amplifier is combined/split only once, i.e.
the relative attenuation of the signal light is relatively small.
[0027] In summary, if the emphasis is placed on the optical amplification of the C band
signal light, the first manner is preferable to be adopted, and if the emphasis is
placed on the optical amplification of the L band signal light, the second manner
is preferable to be adopted, and if the C band and L band are in the same position,
the third manner is preferable to be adopted.
[0028] In addition, the working states of the pumps of the master Raman unit and the slave
Raman unit are mutually monitored each other by detecting the C/L signal in-band optical
power and detecting their pump optical power. Their work flows may be seen in FIG.
4 and FIG. 5.
[0029] The propagation direction of the pump light and the propagation direction of the
signal light may be either the same direction or the opposite direction.
[0030] FIG. 4 is a working flowchart of the master Raman unit.
[0031] After powered on, the master Raman unit determines whether the pump-starting condition
is met, wherein the pump-starting condition includes whether the input signal light
exceeds a corresponding threshold, and whether alarm elements that restrain to start
the pump exist. If the pump-starting condition is not met, this step is repeated.
Once the condition is met, the next step is proceeded to. The purport of this step
is to avoid that the pump is started at an inappropriate time. In fact, the pump-closing
priority is always highest, and determining whether the pump is to be closed will
run through the entire work flow. Once the pump-closing condition is triggered, the
pump-closing instruction is immediately issued and the pump is closed.
[0032] After the pump-starting condition is met, the master Raman unit sets the pump optical
power at a specific small optical power value, such as 50mW, and determines whether
a reflection coefficient exceeds a threshold, if the threshold is exceeded, the low
power mode is remained, otherwise, the next step is proceeded to. The purport of this
step is to avoid excessive reflected light power caused by compelling to increase
the pump power without a qualified reflection coefficient. Meanwhile, as mentioned
above, in this step, it is also always determined whether the pump-starting/pump-closing
condition is satisfied. Once the pump needs to be closed, the closing instruction
of pump is immediately issued, and thus the beginning of the work flow is returned.
[0033] As above mentioned, in the condition that the reflection coefficient does not exceed
the threshold and the pump-starting condition is met, the next step is proceeded to.
In this step, it is determined that whether light power of the C band signal in the
signal light exceeds a threshold, whether light power of the L band signal in the
signal light exceeds the threshold, or whether both light power of the C band signal
and light power of the L band signal exceed the threshold? The purpose of this step
is to determine by what working parameter the master Raman pump unit works in the
next step. Meanwhile, in this step, it is also always determined whether the pump-starting/pump-closing
condition is met and whether the reflection coefficient exceeds the threshold? If
the pump-starting condition is met and the reflection coefficient is abnormal, then
the low power mode is returned to; if the pump-starting condition is not met, the
pump will be closed directly and the beginning of the work flow is returned to. If
the reflection coefficient is normal and the pump-starting condition is met, then
the next step is proceeded to.
[0034] When the light power of the C band signal exceeds the threshold and the light power
of the L band signal is below the threshold, the pump power is configured in a manner
A; when both the light power of the C and L band signals exceeds the threshold, the
master Raman unit configures the pump optical power in a manner B; when the light
power of the C band signal is below the threshold and the light power of the L band
signal is above the threshold, the pump optical power is configured in a manner C.
[0035] The manner A is that the pump power is configured to enable the C band signal gain
to reach a target gain (gain mode) or enable the C band Raman pump light to reach
a target value (power mode) when only the C band signal exists.
[0036] The manner B is that the pump optical power is configured to enable the C+L band
signal gain to reach the target gain (gain mode) or enable the C band Raman pump light
to reach the target value (power mode) when the C band signal and the L band signal
both exist.
[0037] The manner C is that the pump optical power is configured to enable the L band signal
gain to reach the target gain (gain mode) or enable the C band Raman pump light to
reach the target value (power mode) when only the L band signal exists.
[0038] FIG. 5 is a working flowchart of the slave Raman unit.
[0039] The difference from the work flow of the master Raman unit is that the slave Raman
unit only needs to detect the light power of the L band signal without considering
whether the light power of the C band signal exceeds the threshold.
[0040] After powered on, the slave Raman unit determines whether the pump-starting condition
is met, wherein the pump-starting condition includes whether the L band input signal
light exceeds the threshold, and whether alarm elements that restrain to start the
pump exist. If the pump-starting condition is not met, this step is repeated. Once
the condition is met, the next step is proceeded to. The purport of this step is to
avoid to start the pump at an inappropriate time. In fact, the pump-closing priority
is always highest, and determining whether to close the pump will run through the
entire work flow. Once the closing condition of pump is triggered, the closing instruction
of pump is immediately issued and the pump is closed.
[0041] After the pump-starting condition is met, the slave Raman unit sets the pump optical
power at a specific small optical power value, such as 50mW, and determines whether
the reflection coefficient exceeds the threshold. If the threshold is exceeded, the
low power mode is remained, otherwise, the next step is proceeded to. The purport
of this step is to avoid excessive reflected light power caused by compelling to increase
the pump power without a qualified reflection coefficient. Meanwhile, as above mentioned,
in this step, it is also always determining whether the pump-starting/pump-closing
condition is met. Once the pump needs to be closed, the pump-closing instruction is
immediately issued, and thus the beginning of the work flow is returned to.
[0042] As above mentioned, in the condition that the reflection coefficient does not exceed
the threshold and the pump-starting condition is met, the next step is proceeded to,
and the slave Raman pump optical power is increased to the target value, and the determination
is performed continuously: if the pump-starting condition is met but the reflection
coefficient is abnormal, then the low power mode is returned to; if the pump-starting
condition is not met, the pump is closed directly and the beginning of the work flow
is returned to.
[0043] The target value is either a setting value of the L band Raman pump output optical
power (power mode) or a setting value of the signal gain (gain mode).
[0044] The specific embodiments described herein are merely illustration of the spirit of
the present invention. Those skilled in the art to which the present invention belongs
can make various modifications or supplements to the described specific embodiments
or replace them in a similar mode without departing from the spirit of the present
invention or exceeding the scope defined in the appended claims.
1. A self-adaptive wave band amplification method,
characterized in comprising:
a light splitting step for detecting C band detection light and L band detection light
in an in-band signal; and
a scheduling module for enabling a slave Raman amplifying unit to participate in amplification
after the L band detection light is detected.
2. The self-adaptive wave band amplification method of claim 1, characterized in that the scheduling module enables a master Raman amplifying unit after the C band detection
light and/or the L band detection light is detected.
3. The self-adaptive wave band amplification method of claim 1,
characterized in further comprising a wave combining step for performing a wave combination/splitting
by using two optical wavelength division multiplexers after the slave Raman unit injects
its pumping light into a master Raman unit, the wave combination comprising:
injecting pump light from the master Raman amplifying unit into a transmission fiber
after wave combining/splitting once, and injecting pump light from the slave Raman
unit into the transmission fiber after wave combining/splitting twice; or
injecting the pump light from the slave Raman unit into the transmission fiber after
wave combining/splitting once, and injecting the pump light from the master Raman
unit into the transmission fiber after wave combining/splitting twice; or
performing a first wave combination for the pump light from the master and slave Raman
units and then a second wave combination with signal light.
4. The self-adaptive wave band amplification method of claim 1,
characterized in that a work flow of a Raman amplifying unit includes following steps:
step 4.1, determining whether a pump-starting condition is met, and executing step
4.2 if yes;
step 4.2, turning on a Raman unit pump with a preset small optical power value; returning
to step 4.1 when it is determined that the pump-starting condition is not met or executing
step 4.3 when it is determined that a reflection coefficient does not exceed a threshold;
step 4.3, configuring pump power according to a comparison between light power of
each band in signal light and a corresponding threshold, and returning to step 4.1
when it is determined that the pump-starting condition is not met, and executing step
4.2 when it is determined that the reflection coefficient exceeds the threshold.
5. The self-adaptive wave band amplification method of claim 4, characterized in that in the step 4.3,
selecting different working modes for the master Raman unit pump according to the
comparison; and
increasing pump optical power of the slave Raman unit to a target value according
to the comparison.
6. A self-adaptive band amplifier,
characterized in comprising:
a light splitting module for detecting C band detection light and L band detection
light in an in-band signal; and
a scheduling module for enabling a slave Raman amplifying unit to participate in amplification
after the L band detection light is detected.
7. The self-adaptive band amplifier of claim 6, characterized in that the light splitting module comprises: a first signal light splitter for splitting
the in-band signal, and a first optical wavelength division multiplexer connected
with the first signal light splitter, output ends of the first signal light splitter
being respectively connected with a first photodetector and a second signal light
splitter for a master Raman amplifying unit, and the second signal light splitter
being connected with a first photodetector for the slave Raman amplifying unit.
8. The self-adaptive band amplifier of claim 6, characterized in that pump light emitted from a slave Raman amplifying unit pump (3-2) is injected into
a master Raman amplifying unit, passes through a first pump light splitter (4-1) and
is combined with in-band signal light at a second optical wavelength division multiplexer
(2-2), and then is combined at a first optical wavelength division multiplexer (2-1)
with pump light emitted from a master Raman amplifying unit pump (3-1) split by a
second pump light splitter (4-4).
9. The self-adaptive band amplifier of claim 6, characterized in that pump light emitted from a master Raman amplifying unit pump (3-1) passes through
a second pump light splitter (4-4) and is combined with an in-band signal light at
a first optical wavelength division multiplexer (2-1), and then is combined at a second
optical wavelength division multiplexer (2-2) with pump light from a slave Raman amplifying
unit processed by a first pump light splitter (4-1).
10. The self-adaptive band amplifier of claim 6, characterized in that pump light emitted from a master Raman amplifying unit pump (3-1) and pump light
emitted from a slave Raman amplifying unit pump (3-2) are split respectively by a
first pump light splitter (4-1) and a second pump light splitter (4-4) and combined
at an optical wavelength division multiplexer, and then combined with an in-band signal
light by another optical wavelength division multiplexer.